This invention relates to apparatus for moulding a strap on a group of battery plates.
The most common method of moulding straps on groups of battery plates is to invert the group and dip the lugs into a mould filled with molten, but cooling, lead. With thin lugs this is relatively straight forward, because there is sufficient heat in the cooling lead to fuse them and form a good joint. However, as the size of the lugs increase, so does the capacity of the effective heat sink which has been dipped into the molten lead, with the result that the lead can be cooled so rapidly that the submerged surface of the lugs does not melt and no proper joint is formed. In an attempt to overcome this, systems have been developed whereby lead is flowed through the mould, at least during an initial dipping step, so that the lead temperature is initially kept up, but a problem is experienced with lead tails being formed at the outlet, which somehow have to be broken off and removed before the next cycle can take place. Most current proposals suggest the use of the stripper plate, but this provides uneven castings and can even damage the castings. The cycle time is, as a result rather high. Another approach is to interpose a heated triangular section at the lead outlet which provides an adequate transition across the interface between the cooled mould and the heated lead outlet. This however reduces the local effectiveness of the mould cooling and once more increases the cycle time.